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Number

1,987

1,987 is a prime, odd, a calendar year.

1,987 (one thousand nine hundred eighty-seven) is an odd 4-digit number. It is a prime number — divisible only by 1 and itself. Written other ways, in Roman numerals it is MCMLXXXVII and in binary, 11111000011.

Arithmetic Number Cube-Free Deficient Number Odious Number Pernicious Number Prime Recamán's Sequence Sexy Prime Squarefree Year

Interestingness

★ ★ ★ ★ ☆

6 notable facts · grade B

1,975 1,976 1,977 1,978 1,979 1,980 1,981 1,982 1,983 1,984 1,985 1,986 1,987 1,988 1,989 1,990 1,991 1,992 1,993 1,994 1,995 1,996 1,997 1,998 1,999

less more

Notable events — 1987 AD

Feb 23 Supernova SN 1987A is observed — the first naked-eye supernova in nearly 400 years.
Mar 20 The FDA approves AZT as the first drug to treat HIV/AIDS.
Apr 19 The Simpsons debuts as shorts on The Tracey Ullman Show.
Jun 12 Reagan delivers his "tear down this wall" speech at the Brandenburg Gate.
Oct 19 Black Monday: stock markets crash worldwide; the Dow falls 22.6 % in one day.
Dec 8 Reagan and Gorbachev sign the INF Treaty, eliminating intermediate-range nuclear missiles.

Events compiled from Wikipedia ↗ · Licensed CC BY-SA 4.0

Year facts

Year type: Common year
Standard 365-day year; not divisible by 4 (or divisible by 100 but not 400).
Days in year: 365
ISO weeks: 53
Long year: contains 53 ISO weeks.
Started on: Thursday
January 1, 1987
Ended on: Thursday
December 31, 1987
Friday the 13ths: 3
3 Friday the 13ths this year.
Easter Sunday: April 19
Sunday, April 19, 1987
Decade: 1980s
1980–1989
Century: 20th century
1901–2000
Millennium: 2nd millennium
1001–2000
Years ago: 39
39 years before 2026.

In other calendars

Hebrew: 5747 / 5748 AM
Rosh Hashanah falls in September/October.
Islamic Hijri: 1407 / 1408 AH
Lunar calendar; year spans differ from Gregorian.
Chinese: Year of the zodiac:Fire zodiac:Rabbit
Sexagenary cycle position 4 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 2530 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri: 1365 / 1366 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian: 1979 / 1980 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 1909 / 1908 Saka
Indian national calendar; year starts in March.
Japanese: Shōwa 62
Reign-era counting from the start of each emperor's reign.

Properties

Parity: Odd
Digit count: 4
Digit sum: 25
Digit product: 504
Digital root: 7
Palindrome: No
Bit width: 11 bits
Reversed: 7,891
Recamán's sequence: a(3,777) = 1,987
Square (n²): 3,948,169
Cube (n³): 7,845,011,803
Divisor count: 2
σ(n) — sum of divisors: 1,988
φ(n) — Euler's totient: 1,986

Primality

1,987 is prime. It has exactly two divisors: 1 and itself.

Divisors & multiples

All divisors (2)

1 · 1987

Aliquot sum (sum of proper divisors): 1

Factor pairs (a × b = 1,987)

1 × 1987

First multiples

1,987 · 3,974 (double) · 5,961 · 7,948 · 9,935 · 11,922 · 13,909 · 15,896 · 17,883 · 19,870

Sums & aliquot sequence

As consecutive integers: 993 + 994

Continued fraction of √n

√1,987 = [44; (1, 1, 2, 1, 3, 1, 43, 1, 3, 1, 2, 1, 1, 88)]

Period length 14 — the block in parentheses repeats forever.

Representations

In words: one thousand nine hundred eighty-seven
Ordinal: 1987th
Roman numeral: MCMLXXXVII
Binary: 11111000011
Octal: 3703
Hexadecimal: 0x7C3
Base64: B8M=
One's complement: 63,548 (16-bit)
Scientific notation: 1.987 × 10³
As a duration: 1,987 s = 33 minutes, 7 seconds

In other bases

ternary (3) 2201121

quaternary (4) 133003

quinary (5) 30422

senary (6) 13111

septenary (7) 5536

nonary (9) 2647

undecimal (11) 1547

duodecimal (12) 1197

tridecimal (13) b9b

tetradecimal (14) a1d

pentadecimal (15) 8c7

Palindromic in base 13

As an angle

1,987° = 5 × 360° + 187°

187° ≈ 3.264 rad

Compass bearing: S (south)

Why does a circle have 360 degrees? →

Historical numeral systems

Babylonian (base 60): 𒌋𒌋𒌋𒁹𒁹𒁹 𒁹𒁹𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic: 𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺
Greek (Milesian): ͵αϡπζʹ
Mayan (base 20): 𝋤·𝋳·𝋧
Chinese: 一千九百八十七
Chinese (financial): 壹仟玖佰捌拾柒

In other modern scripts

Eastern Arabic ١٩٨٧ Devanagari १९८७ Bengali ১৯৮৭ Tamil ௧௯௮௭ Thai ๑๙๘๗ Tibetan ༡༩༨༧ Khmer ១៩៨៧ Lao ໑໙໘໗ Burmese ၁၉၈၇

Digit at this position in famous constants

π — Pi (π): Digit 1,987 = 3
e — Euler's number (e): Digit 1,987 = 8
φ — Golden ratio (φ): Digit 1,987 = 9
√2 — Pythagoras's (√2): Digit 1,987 = 5
ln 2 — Natural log of 2: Digit 1,987 = 2
γ — Euler-Mascheroni (γ): Digit 1,987 = 5

Also seen as

Prime neighborhood

Adjacent primes:

Previous prime: 1,979 (gap of 8)
Next prime: 1,993 (gap of 6)

Pair status: sexy with 1993.

Unicode codepoint

߃

Nko Digit Three

U+07C3

Decimal digit (Nd)

UTF-8 encoding: DF 83 (2 bytes).

Lookup U+07C3 on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#0007C3

RGB(0, 7, 195)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.7.195.

Address: 0.0.7.195
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.7.195

Unspecified address (0.0.0.0/8) — "this network" placeholder.

Musical pitch

Heard as a frequency, 1,987 Hz is closest to:

Concert pitch (A4 = 440 Hz): B6 (1975.5 Hz, +10¢)
Scientific pitch (C4 = 256 Hz): B6 (1933.1 Hz, +48¢ — about midway to C7)
Baroque pitch (A4 = 415 Hz): C7 (1974.1 Hz, +11¢)

Position in π

The digit sequence 1987 first appears in π at position 8,690 of the decimal expansion (the 8,690ordinal-suffix:th digit after the integer 3).

Search range: the first 1,000,000 fractional digits of π. Any 6-digit-or-shorter string is virtually guaranteed to appear in there — the more interesting signal is the position.

Look up 1987 on Pi Search ↗

Related reading

Prime numbers — The building blocks of arithmetic: what primes are, why they matter, and how we find them.
Egyptian hieroglyphic numerals — Seven hieroglyphs for every power of ten, from a single stroke to a million.